I recently ordered a MI Rail and Vortex optic package from Midwest Industries via telephone. Customer service was fine, shipping was fast and the package price was good. I specifically ordered the new MI/USP rail made for the vortex sparc because it was supposed to have a lower 1/3rd co-witness. I put it together today and the directions that I received were for the regular MI rail system, not the Vortex specific upper rail. There were no pictures or anything in the (Rail or optic) instructions telling me to mount the optic first. I put the upper and lower rails together first and then had to take the upper rail off in order to mount the Sparc. I mounted the sparc with the 4 provided screws and assembled the upper rail back again. The optic was loose. After some cursing, I dug a second bag of smaller screws buried in the optics box. Low and behold those were the ones that were supposed to go on in the first place. Upper rail off again, undid the original 4 long screws and inserted the smaller ones. Upper rail on again, Tightened the screws and optic securily and man was it cool looking. I tested the 2MOA red dot and it worked fine, but there was no 1/3 front/rear sight co-witness. That is the whole reason I bought this package. I'm going to call them tomorrow to see whether they sent me the correct upper rail. Once I get this straightened out, Ill post pics and range results.